Crane attachment for dampening swinging motion

ABSTRACT

The description discloses a crane which has an apparatus for dampening swinging motion of a load. This is accomplished by means, mounted to the crane, for allowing motion of the load in two separate planes and means for braking the movement of the load within each of said planes. The load may be restrained for movement in one plane by rotatably connecting the lifting end of the crane boom about the longitudinal axis of the boom and the load may be restrained within the other plane by pivotally connected a cable restraining means to said lifting end of the boom. Selective braking action to the load within the planes dampens its swinging movement.

'ijnited @tates Patent [1 1 Mundy [45-] NEW. 26, 1974 1 1 CRANEATTACHMENT FOR DAMPENING SWINGING MOTIUN [75] Inventor: Charles S.Mundy, San Diego, Calif.

[22] Filed: Nov. 3, 1966 [21] Appl. No: 591,932

[56] References Cited UNITED STATES PATENTS Senn 212/58.1 McLean2l2/58.1 Gercke 212/58.1 Heikkinen 294/67.1 A

3,401,804 9/1968 Link 212/58 Primary ExaminerEvon C. Blunk AssistantExaminer-Bruce H. Stoner, Jr. Attorney, Agent, or Firm-R. S. Sciascia;P. N. Critchlow [5 7 ABSTRACT The description discloses a crane whichhas an apparatus for dampening swinging motion of a load. This isaccomplished by means, mounted to the crane, for allowing motion of theload in two separate planes and means for braking the movement of theload within each of said planes. The load may be restrained for movementin one plane by rotatably connecting the lifting end of the crane boomabout the longitudinal axis of the boom and the load may be restrainedwithin the other plane by pivotally connected a cable restraining meansto said lifting end of the boom. Selective braking action to the loadwithin the planes dampens its swinging movement.

12 Claims, 4 Drawing Figures PATENTELNnv2sm4 SHEET 10F 2 INVENTOR.

CHARLES S. MUN DY ATTORNEY.

PATENTEL NOVZBIQH 306 SHEET 2 OF 2 INVEN'IUR CHARLES S. MUN DY ATTOR N EY.

CRANE ATTACHMENT FOR DAMPENING SWINGING MOTION The present inventionrelates to a crane attachment for dampening swinging motion of a load,and particularly to an apparatus which attaches to a lifting cable cranefor selectively dampening the swinging motion of a load being carried bythe crane.

Problems have always existed with regard to the operation of a liftingcable crane in that a load suspended from the crane has a tendency to gothrough random swinging motions due to external forces acting on thecrane and the load. Such swinging motions can occur whether the crane beon land or at sea. A land based crane is highly susceptible to strongwinds which may cause the load which is being raised or lowered to startswinging. A rocking of the crane base caused by a shifting of the groundunderneath the crane may also cause a swinging motion in the load, andload swinging motion may be introduced by the mere operation of thecrane as it moves the load from one location to another. The loadswinging motion becomes even more acute when the crane is located aboarda ship which is constantly subjected to wave actions. Not only do waveactions effect the ship and, therefore, the crane but also strong windsmay combine to make sea loading or unloading a particularly hazardousundertaking. Such undertakings are hazardous to both property as well aspersonnel since on land and on board a ship building structures arealmost always in close proximity to the crane. In addition, there areusually a number of workers in the vicinity of the crane including thosewhoe job it is to attach or detach the load from the crane, observersand related personnel.

Special problems exist when the crane is used to carry out scientificexperiments at sea since it is quite common for a crane to be used tomove a heavy instrument package from the deck of a ship into the waterand then drag the package in the water for a certain period of time.While the sea might have been calm when the heavy package was originallyplaced in the water at the beginning of the experiment, it often happensthat upon conclusion of the experiment the sea has roughenedconsiderably. Therefore, the job of raising the heavy load out of thewater and replacing it back on board the ship becomes a very complicatedand highly dangerous job, for not only is the ships crew in danger fromthe swinging load but also the ship itself because the momentum gainedby a heavy swinging load can be considerable and has been known tobuckle ship plating.

Two additional problems caused by a swinging load are: an adverse effecton cable life expectancy and excessive bending moments upon the crane.The more the load is allowed to swing the greater are the stresses andstrains put upon the cable and the crane. By reducing or eliminating theswinging motion a particular size crane will have an increased capacityfor lifting and lowering and cable life can be extended.

The present invention has solved all of the above mentioned problems byits ability to selectively dampen the swinging motion of a load which iseither being raised or lowered; therefore, danger to personnel isgreatly reduced, danger to property is reduced, and cable life and cranecapacity are extended. In a preferred embodiment of the invention theproblems are solved by combining with a lifting cable crane an apparatuscomprising a stiff connector connected at one end to the lifting cableand at the other end to the load, retainer means for coacting with thestiff connector, means for pivotally connecting the retainer means tothe crane for engaging the stiff connected to dampen swinging motion ofthe load and for disengaging the stiff connector so that the load isfree from said retainer means, braking means, means for connecting thebraking means to the crane, means including the retainer means forconnecting the braking means to the load when the stiff connector isengaged with the retainer means, said braking means for braking pivotalmovement of the retainer means so that a swinging motion of the load isretarded when the stiff connector and the retainer means are engaged.

It is pointed out that while a preferred embodiment comprises thebraking means, the stiff connector and the retainer means incombination, dampening may also be achieved with just a braking means orwith just the combination of a stiff connector and retainer meansapparatus. While each of the above embodiments is able to dampenswinging motions to a certain extent the preferred embodimentcombination, as shown in the drawings, is a more effective and efficientdampening apparatus.

Reiterating, the advantages of the present invention are threefold: lthe potential danger to personnel and property is greatly reduced oreliminated; (2) cable life expectancy is greatly extended; and (3) cranelifting capacity is greatly increased. While all of the above advantagesare achieved, the apparatus has not resulted in any new disadvantages.

An object of the present invention is to provide an apparatus for alifting cable crane which will allow the crane to raise and lower heavyobjects without danger to personnel and property from a swinging motionof the load, said apparatus being able to selectively, easily, andefficiently dampen the swinging motion of the load.

Another object of the present invention is to provide an apparatus for alifting cable crane which will extend cable life.

A further object of the present invention is to provide an apparatus fora lifting cable crane which will enable the crane to achieve a greaterlifting capacity.

Still another object of the present invention is to achieve all of theforegoing advantages with a simply constructed and easily operableapparatus which is attachable to a lifting cable crane.

Other objects, advantages and novel features of the invention willbecome apparent from the following detailed description of the inventionwhen considered in conjunction with the accompanying drawings wherein:

FIG. 1 shows an ocean going vessel and a lifting cable crane whichutilizes the present invention to dampen swinging motion of the load ina rough sea;

FIG. 2 is a partially cut away side view of a preferred embodiment ofthe invention mounted at the end of the crane;

FIG. 3 shows a front view of the embodiment as seen from the right sideof FIG. 2;

FIG. 4 is a plan section view of two locking chops taken on the planeIV-IV of FIG. 3 looking in the direction of the arrows.

Referring now to the drawings, wherein like reference numerals designatelike or corresponding parts throughout the several views, there is shownin FIG. 1 a seagoing vessel 10 with an articulated" crane 12 locatednear the stern end of the vessel. An articulated crane is one that has ajointed crane boom 16, the joint for this crane being at 14. The use ofa joint enables far more flexibility than can be achieved with just astraight one piece boom. The actual location of the preferred embodimentof the invention is at the lifting end I8 of the crane so as to be inclose proximity to the load 20. In normal use an articulated craneoperates by being able to move at its center joint 14 as well as atpivot 22, to allow the crane end IS a considerable degree of freedom.Therefore, the heavy load 20 when on deck 24 may be attached to thecrane then raised, moved over the side and lowered adjacent the waterall without the necessity of unreeling the cable. In the particularapplication shown in FIG. I the heavy load 20 may be a scientificinstrument package which is intended to be lowered into the water andthen dragged at a desired depth below the ship for a certain period oftime or for a certain distance. The articulated crane is able to lowerthe load almost to the level of the water before it becomes necessary tounreel the cable. Likewise when retrieving the heavy load the crane 12may be lowered as close to the water as is possible and then the cableis rewound.

The main difficulties encountered when operating an articulated craneor, for that matter, any crane aboard a moving vessel is that there is agreat deal of rolling and pitching motion occasioned by rough seasand/or high winds. The rough seas act upon the ship in three ways, thefirst being a pitching motion whereby the ship will be moved about anaxis transverse to the ship so that the bow will be alternately raisedand lowered by the waves. The second set of motions will be rolling,which is motion around the longitudinal (bow to stem) axis. And thethird set of motions is about a vertical axis as the ship is propelledthrough the water. When these three sets of motions are put together thereference plane of the crane becomes extremely mobile. The forces set upby the motions of the ship are transmitted to the crane l2 and then tothe load causing the load to have a tendancy to swing haphazardly. It isthe undesirable swinging motion of the load 20 that the presentinvention retards or eliminated. It should also be noted that a groundcrane is also subjected to forces which tend to move its reference planesuch as soft or shifting ground, or the momentum built up by merelymoving a heavy object. The crane is also subjected to the possibility ofhigh winds even though it be upon solid ground. Therefore, the presentinvention apparatus is adaptable to cranes, articulated or otherwise,under conditions where the crane may be on a seagoing vessel or at somestationary location upon land.

The preferred embodiment of the present invention is shown in moredetail in FIGS. 2 and 3. As mentioned earlier, the invention may beattached at the end 18 of the crane. The preferred invention is allowedtwo degrees of motion, that is, the apparatus has the ability to rotatein two different planes. The first plane may be considered to becoincident with the surface of the drawing in FIG. 3 with rotationoccurring about an axis located at 26. When the load is attached thisrotational motion will allow the load to rotate laterally with respectto the crane. The second degree of rotation occurs about an axis 28,FIG. 2, which allows rotation in the plane of drawing as shown in FIG.2. superimposing the two degrees of rotational motion allows arelatively free degree of movement by the load 20. Thus, each axispermitting the above rotation serves as a gimbal permitting movement bythe load 20.

When the articulated crane is placing the load into the water the craneis near one of its fully extended positions so that there will berotation about the axis 28 until the load is almost linear extension ofthe end of the crane. If there is movement of the ship at the same timethen there will be a rotation of the apparatus about axis 26 also.During retrieval of the load 2Il-the apparatus will be rotated as justdescribed until the load is pulled out of the water at which point thedragging force of the water against the load will no longer be presentto dampen swinging motion. If the vessel It) is rolling or pitching toany great degree the forces will then act upon the load 20 causing it tostart its swinging motion.

The dampening apparatus comprises braking means which may include twobraking units 30 and 32, FIG. 2, and means for connecting the brakingmeans to the crane such as shroud 34 which may be welded to an innerhollow shaft 36 received therein. The hollow shaft 36 is rotatablymounted within and supported by a housing 38 intermediate the ends ofthe boom I6, the housing being mounted to the boom in any suitablemanner such as by having upwardly extending welded ears 40 and 42 whichare bolted to the boom as shown in FIG. 2. A means for connecting thebraking means to the load which may comprise two supporting channelmeans 44 and 46, FIG. 3, between which cable or painter 48 may pass. Thepreferred apparatus also comprises a stiff connector 50, FIG. 2, whichis connected at its upper end to the cable 48 and at its opposite end tothe load 20. The stiff connector 50 may be of a generally cylindricalshape with an eyelet 52 for receiving cable 48 and a slot with two bolts99 and at its lower end adapted so that it may be securely attached bybolts to the load 20. The apparatus is further comprised of a retainermeans or load adaptor 54, FIG. 3, which may be of a cylindrical tubedesign so as to re ceive the stiff connector 50, and means for pivotallyconnecting the retainer means 54 to the lifting end of the boom 18,which may include the two channel elements 44 and 46 which are in turnpivotally supported by the shroud 34.

All of the apparatus except for the housing 38 and part of the firstbrake unit 30 is rotatable about the axis 26 in the plane of the drawingof FIG. 3. The elements that rotate about axis 28 in the second plane,that is the plane of the drawing in FIG. 2, are part of the second brakeunit 32, the two supporting channel means 44 and 46, the retainer means54, and the load 20. There fore, it is this last group of elements whichare adapted to be rotatable about both. of the planes of motion alreadymentioned. The preferred embodiment is completed by having holding meanswhich may be locking chops 58 and 60, FIG. 4, pivotally connected to theretainer means 54 and in turn the supporting channel means 44 and 46.The locking chops are adapted to engage the stiff connected 5!) in oneposition (solid lines of FIG. 4) and disengage the stiff connector inanother position (phantom lines of FIG. 4).

While the preferred embodiment includes all the elements listed above,an apparatus including only several of the elements in combination mayalso give improvement in the control of swinging motion of the load.Hence, an apparatus which does not have the second brake unit, the stiffconnector, or the retainer means but only the first brake unit 30, mayprovide an improvement in load swing control. The rotation about axis 26may be controlled by the first brake unit 30 which may be comprised of arotatable element such as an outer drum 62 which is mounted on thehollow shaft 36 and rotatable therewith, and a stationary element 64which may be mounted on housing 38 and comprised of several segmentedinflatable bladders of a friction material. The bladders may behydraulically inflated through hose 66 causing the bladder 64 to expandand engage rotatable element 62 for effective braking. This brakingmotion would tend to retard the swinging motion of the load about axis26 which is the axis of rotation of the hollow shaft 36 as it rotateswithin housing 38. The housing 38 may contain a sleeve bearing 68 forreceiving the shaft 36. It should be noted that a major advantage isgained by having rotation about axis 26 when axis 26 is coincident withthe longitudinal axis of the cable 48, as it passes through shaft 36;for to have such causes the least amount of stresses and strains on thecable due to rotational motion. If the longitudinal axis of the cable isnot coincident with the axis 26 then there will be a certain degree oftwisting and distorting of the cable 48 causing rapid wear and resultingin shortened cable life.

An apparatus which comprises only the stiff connector 50, the retainermeans 54 and means for connecting the retainer means to the crane wouldalso offer an improvement in controlling the swinging motion of theload. The swinging motion may be controlled by having the retainer meanscoact with the stiff connector, such as by engagement. The meansconnecting the retainer means tothe crane enables the stiff connectorand retainer means to engage to dampen swinging motion and to disengageso that the load is free from the retainer means. In the engagedposition the stiff connector 50 may be adapted to fit snugly within theretainer means 54. By preventing rotation about axis 28 and having asnug engagement between the stiff connector and the retainer means,swinging motion is dampened. This snug arrangement would also preventthe cable 48 from leaving the groove of the sheave 56. The mainadvantage is that the cable is better protected and has less stress andstrain upon it. Therefore cable life is extended while at the same timethe swinging motion of the load is restricted.

When an apparatus includes the first and second braking units 30 and 32in addition to the stiff connector 50, the retainer means 54 and themeans for connecting the retainer means to the crane, not only is thecable life extended but more effective control is achieved over therotation motion about axis 28. Brake 32 may be comprised of a stationaryelement, such as clamps 70, and a movable element, such as discs 72.Each of the clamps 70 may be a pair of friction discs (not shown) whichare oppositely disposed within a housing (seen in FIG. 2) and inwardlydriven to make engagement with opposite sides of a respective disc '72by hydraulic pressure through lines 74. These clamps have the trade nameof Calipers" and may be purchased from Goodyear Corporation. The clamps70 may be connected to a frame assembly 71 which in turn is welded tothe shroud 34. The clamps 79 are accordingly stationary relative torotational movement about the axis 28 but are rotatable about axis 26since the shroud 34 is connected to and is rotatable with the movabledrum 62 of the first brake unit. Each of the discs 72 may be connectedto a respective channel support 44 or 46 by a bolted-on hub 73 whichreceives the shaft at 28 and is in turn rigidly connected to the channelsupport by any suitable means such as welding. The two channel supports44 and 46 form a relatively rigid connection with the load 20 by way ofthe stiff connector 50 and the retainer means 54. An operatorselectively applying hydraulic pressure through the hoses '74 may beselectively retard the disc '72.. Thus the advantages achieved by theapparatus having the two brake units and the snug engagement of thestiff connector and the retainer means provides retardation of theswinging motion in two planes, one perpendicular to the other, as wellas providing extended cable life by keeping the cable aligned within thegroove of the sheave 56 and by causing rotation about an axis coincidentwith the axis cable 48.

By adding the last major feature, that is the locking chops 58 and 60,to an apparatus containing the two brake units, the stiff connector andthe retainer means, the complete preferred embodiment is created. Thelocking chops are actuated by a tubular hydraulic actuator whichreceives two oppositely spaced shafts 76 and '78 which may beselectively actuated by hydraulic fluid flowing through hose 82 into theactuator between the shaft ends. The locking chops 58 and 60 arepivotally connected at 82 and 84 to chop guides 86, 88, and 92 which arelocated in pairs above and below each of the locking chops so that thechops may pivot from a disengaged position (shown in phantom lines inFIG. 4) to an engaged position (shown in solid lines in FIG. 4) with thestiff connector. The chop guides 86, 88, 90 and 92 are in turn rigidlyconnected to the channels 44 and 46 by any suitable means such aswelding. An annular depression 96 may be placed in the stiff connector50 so that when the stiff connector is in a snug position within theretainer means 54 the locking chops extend through opposite slots in theretainer and engage the annular depression 96 and support the stiffconnector 50 as shown in FIG. 2. The main advantage of having thelocking chops is that when in the engaged look ing position the weightof the load 20 is no longer carried by the cable 48 but is transferredthrough the locking chops to the channel supports i4 and 46 and thenceback to the crane end 18. As explained earlier, since an articulatedcrane has the ability to retain the load close to the crane end 18during much of the movement of the heavy load, a considerable extensionof cable life can be achieve as the cable is not carrying any of theload. Also the entire apparatus becomes relatively rigid since the stiffconnector may be blocked at one end by the locking chops and at theother end by an annular positioning block 98 which locates the stiffconnector in the proper position for the locking chops to engage. Thus,the relatively rigid formation enables the brake units 30 and 32 to moreeffectively operate to retard the swinging motion of the load becauseall of the swinging motion will take place about the two axes 26 and 28.

OPERATION Operation of the inventive apparatus is extremely simple,effective and efficient. The articulated crane 12 is able to move aboutits pivot points 14.- and 22 to bring its end 18 in close proximity to aload 26 upon the deck 24 of a vessel 10. The load may then be attachedas shown in FIG. 2 to the stiff connector 50 by any convenient methodsuch as the bolts at 99 and 100. By having locking chops 58 and 60 intheir engaged position with the stiff connector 50 so that a relativelystiff connection is achieved between the load and the crane, the weightof the load is carried by the locking chops 58 and 60 rather than thecable 48. The crane may then lift the load off the deck 24 and move itover the side of the ship and then down to the cranes 'lowerlimit whichshould place the weight 20 just above the water level. It is during thistime when the weight 20 is being moved from the deck to the water levelthat a swinging motion of the weight may occur in the two planardirections mentioned earlier. The operator by selectively feedinghydraulic fluid into hoses 66 and 74 may cause the brake units and 32 toretard the swinging motions in their respective planes. Once the cranehas reached its lower limit the locking chops are moved into theirdisengaged position by relieving the hydraulic fluid from line 82causing the actuator shafts 76 and 78 to retract within the actuator 80thereby pivoting the locking chops. The load then becomes suspended bythe cable and is lowered into the water to the desired depth. It shouldbe noted that at no time does the load have extreme swinging motionswhich cause the jerking and severe stress and strain in the cable 48 orthe severe bending moment forces on the crane 12. Thus, the

. cable life is extended and the crane is able to lift larger weightloads. The actuator shafts '76 and 78 may be retracted by a springwithin the actuator 80.

Once the weight is at the desired depth there will be little or noexcessive swinging motions as the drag of the water tends to stabilizethe load. When the experiment is finished the crane is again lowered toits limit just above the water line and the cable is reeled in until thestiff connector abuts the annular positioning block 98. The operator maythen feed hydraulic fluid through line 82 to actuate the locking chops58 and to their engaging and locking position with regard to the annulardepression 96 of the stiff connector 50. Once again, the weight of theload is removed from the cable 48 and is taken up by the locking chopsand transmitted back to the crane. The load 20 is then lifted backaboard the ship while the operator selectively activates the brake units30 and 32 to prevent excessive swinging motions. Thus, not only can theentire operation be done in considerably more safety, but the entireoperation may be done far more efficiently and in considerably less timewith considerably less chance of failure of the crane or the cable.

Obviously many modifications and variations of the present invention arepossible in the light of the above teachings. It is therefore to beunderstood that within the scope of the appended claims the inventionmay be practiced otherwise than as specifically described.

I claim:

1. in combination with a lifting cable crane, apparatus to substantiallydampen swinging motion of a load suspended from the cable comprising:

a stiff connector connected at one end to the lifting cable and at anopposite end to the load;

retainer means for restrainably engaging said stiff connector;

means pivotally connecting the retainer means to the crane;

braking means;

means for connecting the braking means to the crane; and

means including the retainer means for connecting the braking means tothe load when the stiff connector is engaged with the retainer means,said braking means for braking pivotal movement of the retainer means sothat swinging motion of the load is retarded when the stiff connectorand the retainer are engaged.

2. An apparatus as claimed in claim 1 wherein the braking meanscomprises:

a first brake unit; and

a second brake unit,

the second brake unit being disposed in a perpendicular relationship tothe first brake unit,

whereby the first brake unit retards swinging motion in a first planeand the second brake unit retards swinging motion in a second planeperpendicular to the first plane.

3. An apparatus as claimed in claim 1 wherein the stiff connectorcomprises:

a generally cylindrical member;

said retainer means being adapted to receive said cylindrical member.

4. An apparatus as claimed in claim 1 wherein the retainer meanscomprises:

a cylindrical tube disposed about the lifting cable and adapted tosnugly receive the stiff connector when engaged therewith.

5. An apparatus as claimed in claim 1 wherein the retainer meanscomprises:

a cylindrical tube disposed about the lifting cable and adapted tosnugly receive the stiff connector when engaged therewith; and

holding means connected to the crane for engaging the stiff connectorand supporting the load when the connector is received within theretainer means so that the weight of the load is transferred from thelifting cable to the crane.

6. An apparatus as claimed in claim 5 wherein:

the stiff connector is a generally cylindrical member;

the cylindrical member being adapted to fit snugly within thecylindrical tube;

the holding means comprises pivotally connected locking chops adapted topivot from a disengaging to an engaging position with respect to thecylindrical stiff connector;

the cylindrical stiff connector having an annular depression forreceiving the locking chops; and in-' cluding an annular block connectedwithin the cylindrical tube for positioning the stiff connector toreceive the locking chops within said annular depression.

7. An apparatus as claimed in claim 1 wherein:

a cylindrical housing is mounted to the crane;

a hollow shaft is rotatably mounted and supported within the housing andadapted to receive the cable therethrough;

a first brake unit having a stationary element and a rotatable elementis supported by the housing, the stationary element being attached tothe housing, the rotatable element being attached to the rotat ableshaft and being rotatable in a plane perpendicular to the axis of theshaft;

a second brake unit having a stationary element relative to therotatable element of the first brake unit and a rotatable element, saidrotatable element of the second brake unit being rotatable in a planeperpendicular. to the plane of rotation of the rotatable element of thefirstbrake unit;

shroud means rotatable with the rotatable element of the first brakeunit for connecting said stationary element of the second brake unit tothe rotatable element of the first brake unit;

a sheave means rotatably connected to said shroud means for receivingthe cable and aligning the cable along the longitudinal axis of thehollow shaft;

the retainer means comprises a cylindrical tube disposed about a sectionof cable between the load and the sheave means;

channel means for pivotally supporting and connecting the tube to therotatable element of the second brake unit; and

locking chops pivotally connected to the channel means and adapted topivot from a disengaging to an engaging position with respect to thestiff connector,

the stiff connector being a generally cylindrical member having anannular depression for receiving the locking chops,

whereby the locking chops support the load by engaging the annulardepression of the stiff connec- [01.

8. In combination with a crane which has a swinging boom and a sheavemounted at the lifting end of the boom, apparatus for dampening swingingmotion of a load suspended from a cable over said sheavecomprisrotatable means including brake means located intermediate theends of the boom for rotatably connecting the lifting end of the boomand the sheave about the longitudinal axis of the boom;

cable restraining means pivotally connected to the lifting end of theboom for restraining movement of the load within the plane of thesheave; and

means connected to the boom for selectively braking pivotal movement ofthe cable restraining means, whereby swinging motion of the load can beselectively dampened in two planes of movement.

9. In a crane having a boom and means for elevating the boom, theimprovement comprising:

a. a jib pivotally connected to the boom;

b. means connected to the jib for pivotally raising and lowering samewith respect to the boom;

0. a gimbal connected to the jib;

d. a load adapter mounted upon said gimbal, said load adapter includingmeans for guiding a painter, and

e. controllable braking means for constraining the movement of said loadadapter with respect to said jib.

10. The improvement in a crane as defined in claim 9 wherein the gimbalis a two-axis gimbal and wherein said controllable braking means areseparately controllable on each of the axes.

11. In a crane having a boom and means for elevating the boom, theimprovements comprising:

a. a jib having a proximal end and a distal end, the

proximal end being pivotally attached to the boom;

b. means connected to the jib for pivotally raising and lowering thedistal end thereof with respect to the boom;

0. a gimbaled load adapter connected to the distal end of said jib, saidload adapter including means for guiding a painter, and

d. controllable braking means for constraining the movement of said loadadapter with respect to said jib.

12. In a crane having a boom and means for elevating the boom, theimprovement comprising a gimbaled load adapter, said load adapterincluding means for guiding a painter, and controllable braking meansfor constraining the movement of said load adapter.

* l I l

1. In combination with a lifting cable crane, apparatus to substantiallydampen swinging motion of a load suspended from the cable comprising: astiff connector connected at one end to the lifting cable and at anopposite end to the load; retainer means for restrainably engaging saidstiff connector; means pivotally connecting the retainer means to thecrane; braking means; means for connecting the braking means to thecrane; and means including the retainer means for connecting the brakingmeans to the load when the stiff connector is engaged with the retainermeans, said braking means for braking pivotal movement of the retainermeans so that swinging motion of the load is retarded when the stiffconnector and the retainer are engaged.
 2. An apparatus as claimed inclaim 1 wherein the braking means comprises: a first brake unit; and asecond brake unit, the second brake unit being disposed in aperpendicular relationship to the first brake unit, whereby the firstbrake unit retards swinging motion in a first plane and the second brakeunit retards swinging motion in a second plane perpendicular to thefirst plane.
 3. An apparatus as claimed in claim 1 wherein the stiffconnector comprises: a generally cylindrical member; said retainer meansbeing adapted to receive said cylindrical member.
 4. An apparatus asclaimed in claim 1 wherein the retainer means comprises: a cylindricaltube disposed about the lifting cable and adapted to snugly receive thestiff connector when engaged therewith.
 5. An apparatus as claimed inclaim 1 wherein the retainer means comprises: a cylindrical tubedisposed about the lifting cable and adapted to snugly receive the stiffconnector when engaged therewith; and holding means connected to thecrane for engaging the stiff connector and supporting the load when theconnector is received within the retainer means so that the weight ofthe load is transferred from the lifting cable to the crane.
 6. Anapparatus as claimed in claim 5 wherein: the stiff connector is agenerally cylindrical member; the cylindrical member being adapted tofit snugly within the cylindrical tube; the holding means comprisespivotally connected locking chops adapted to pivot from a disengaging toan engaging position with respect to the cylindrical stiff connector;the cylindrical stiff connector having an annular depression forreceiving the locking chops; and including an annular block connectedwithin the cylindrical tube for positioning the stiff connector toreceive the locking chops within said annular depression.
 7. Anapparatus as claimed in claim 1 wherein: a cylindrical housing ismounted to the crane; a hollow shaft is rotatabLy mounted and supportedwithin the housing and adapted to receive the cable therethrough; afirst brake unit having a stationary element and a rotatable element issupported by the housing, the stationary element being attached to thehousing, the rotatable element being attached to the rotatable shaft andbeing rotatable in a plane perpendicular to the axis of the shaft; asecond brake unit having a stationary element relative to the rotatableelement of the first brake unit and a rotatable element, said rotatableelement of the second brake unit being rotatable in a planeperpendicular to the plane of rotation of the rotatable element of thefirst brake unit; shroud means rotatable with the rotatable element ofthe first brake unit for connecting said stationary element of thesecond brake unit to the rotatable element of the first brake unit; asheave means rotatably connected to said shroud means for receiving thecable and aligning the cable along the longitudinal axis of the hollowshaft; the retainer means comprises a cylindrical tube disposed about asection of cable between the load and the sheave means; channel meansfor pivotally supporting and connecting the tube to the rotatableelement of the second brake unit; and locking chops pivotally connectedto the channel means and adapted to pivot from a disengaging to anengaging position with respect to the stiff connector, the stiffconnector being a generally cylindrical member having an annulardepression for receiving the locking chops, whereby the locking chopssupport the load by engaging the annular depression of the stiffconnector.
 8. In combination with a crane which has a swinging boom anda sheave mounted at the lifting end of the boom, apparatus for dampeningswinging motion of a load suspended from a cable over said sheavecomprising: rotatable means including brake means located intermediatethe ends of the boom for rotatably connecting the lifting end of theboom and the sheave about the longitudinal axis of the boom; cablerestraining means pivotally connected to the lifting end of the boom forrestraining movement of the load within the plane of the sheave; andmeans connected to the boom for selectively braking pivotal movement ofthe cable restraining means, whereby swinging motion of the load can beselectively dampened in two planes of movement.
 9. In a crane having aboom and means for elevating the boom, the improvement comprising: a. ajib pivotally connected to the boom; b. means connected to the jib forpivotally raising and lowering same with respect to the boom; c. agimbal connected to the jib; d. a load adapter mounted upon said gimbal,said load adapter including means for guiding a painter, and e.controllable braking means for constraining the movement of said loadadapter with respect to said jib.
 10. The improvement in a crane asdefined in claim 9 wherein the gimbal is a two-axis gimbal and whereinsaid controllable braking means are separately controllable on each ofthe axes.
 11. In a crane having a boom and means for elevating the boom,the improvements comprising: a. a jib having a proximal end and a distalend, the proximal end being pivotally attached to the boom; b. meansconnected to the jib for pivotally raising and lowering the distal endthereof with respect to the boom; c. a gimbaled load adapter connectedto the distal end of said jib, said load adapter including means forguiding a painter, and d. controllable braking means for constrainingthe movement of said load adapter with respect to said jib.
 12. In acrane having a boom and means for elevating the boom, the improvementcomprising a gimbaled load adapter, said load adapter including meansfor guiding a painter, and controllable braking means for constrainingthe movement of said load adapter.